Solar-light-driven LaFe x Ni1- x O3 perovskite oxides for photocatalytic Fenton-like reaction to degrade organic pollutants.

LaFe x Ni1- x O3 perovskite oxides were prepared by the sol-gel method under various conditions, including different pH values (pH 0 and pH 7) and different calcination temperatures (500-800 °C) as well as different Fe/Ni ratios (1/9, 3/7, 5/5, 7/3, 9/1). The samples were examined by XRD, DRS, BET, and SEM to reveal their crystallinity, light-absorption ability, specific surface area, and surface features, respectively. The photocatalytic Fenton reaction was conducted using various LaFe x Ni1- x O3 perovskite oxides to decompose the methylene blue molecules. Accordingly, the synthesis condition of pH 0, calcination temperature at 700 °C, and Fe/Ni ratio = 7/3 could form LaFe0.7Ni0.3O3 perovskite oxides as highly efficient photocatalysts. Moreover, various conditions during the photocatalytic degradation were verified, such as pH value, catalyst dosage, and the additional amount of H2O2. LaFe0.7Ni0.3O3 perovskite oxides could operate efficiently under pH 3.5, catalyst dosage of 50 mg/150 mL, and H2O2 concentration of 133 ppm to decompose the MB dye in the 1st order kinetic rate constant of 0.0506 s-1.

Generation of Concentric Space-Variant Linear Polarized Light by Dielectric Metalens.

Miniaturized flat and ultrathin optical components with spatial and polarization degrees of freedom are important for optical communications. Here, we use nanostructures that act as tiny phase plates on a dielectric metalens to generate a concentric polarization beam with different orientations along the radial direction. The important discoveries are that (1) the circularly polarized light can be converted into linearly polarized states with a different orientation at near field and that (2) this orientation is strongly correlated to the rotation of the nanostructures on the metalens. Stokes parameters are utilized to investigate the comprehensive polarization states embedded in the optical intensity along the propagation direction. The variation of the spatial polarization states transformed by the dielectric metalens can be properly mapped onto the Poincaré sphere. We believe that the variety of spatial polarizations within a miniaturized configuration provides a new degree of freedom for diverse applications in the future.

Host Plant-Derived miRNAs Potentially Modulate the Development of a Cosmopolitan Insect Pest, Plutella xylostella.

Plant microRNAs (miRNAs) have recently been reported to be involved in the cross-kingdom regulation of specific cellular and physiological processes in animals. However, little of this phenomenon is known for the communication between host plant and insect herbivore. In this study, the plant-derived miRNAs in the hemolymph of a cruciferous specialist Plutella xylostella were identified by small RNAs sequencing. A total of 39 miRNAs with typical characteristics of plant miRNAs were detected, of which 24 had read counts ≥ 2 in each library. Three plant-derived miRNAs with the highest read counts were validated, and all of them were predicted to target the hemocyanin domains-containing genes of P. xylostella. The luciferase assays in the Drosophila S2 cell demonstrated that miR159a and novel-7703-5p could target BJHSP1 and PPO2 respectively, possibly in an incomplete complementary pairing mode. We further found that treatment with agomir-7703-5p significantly influenced the pupal development and egg-hatching rate when reared on the artificial diet. The developments of both pupae and adults were severely affected upon their transfer to Arabidopsis thaliana, but this might be independent of the cross-kingdom regulation of the three plant-derived miRNAs on their target genes in P. xylostella, based on expression analysis. Taken together, our work reveals that the plant-derived miRNAs could break the barrier of the insect mid-gut to enter the circulatory system, and potentially regulate the development of P. xylostella. Our findings provide new insights into the co-evolution of insect herbivore and host plant, and novel direction for pest control using plant-derived miRNAs.

GeSn resonant-cavity-enhanced photodetectors on silicon-on-insulator platforms.

We report GeSn p-i-n resonant-cavity-enhanced photodetectors (RCEPDs) grown on silicon-on-insulator substrates. A vertical cavity, composed of a buried oxide as the bottom reflector and a deposited SiO2 layer on the top surface as the top reflector, is created for the GeSn p-i-n structure to enhance the light-matter interaction. The responsivity experiments demonstrate that the photodetection range is extended to 1820 nm, completely covering all the telecommunication bands, because of the introduction of 2.5% Sn in the photon-absorbing layer. In addition, the responsivity is significantly enhanced by the resonant cavity effects, and a responsivity of 0.376 A/W in the telecommunication C-band is achieved that is significantly higher than that of conventional GeSn-based PDs. These results demonstrate the feasibility of CMOS-compatible, high-responsivity GeSn-based PDs for shortwave infrared applications.

[Improvement of the the thermostability of Penicillium expansum lipase by mutagenesis the random mutant ep8 at K55R].

In order to improve the thermostability of the Penicillium expansum Lipase (PEL), the lipase encoding genes was mutated by site-directed mutagenesis. A recombinant vector pAO815-ep8-K55R which contain double mutant genes was constructed by overlap extension PCR using the cDNA of a random-mutant lipase ep8 (a single site mutant) as the template and two special primers were used to generate another mutation site K55R. The recombinant vector was transformed into Pichia pastoris GS115 by electroporation and the recombinant mutant GS-pAO815-ep8- K55R can secret double-mutant lipase PEL-ep8-K55R-GS into the medium when it was induced by Methanol. The yield of the double-mutant lipase is 508 u/mL, which is 81% that of the wild type lipase PEL-GS (627 u/mL) and 55% that of random-mutant PEL-ep8-GS (924 u/mL). The specific activity of double-mutant lipase is 2309.1 u/mg, which is similar to random-mutant lipase PEL-ep8-GS and the wild type lipase PEL-GS. The optimum temperature of the double-mutant lipase is same with the wild type lipase PEL-GS and random-mutant lipase PEL-ep8-GS. While the Tm of the double-mutant lipase is 41.0 degrees C, 2.3 degrees C higher than the wild type lipase PEL-GS and 0.8% higher than the random-mutant lipase PEL-ep8-GS, indicating that the double-mutant lipase PEL-ep8-K55R-GS has higher thermostability.